scholarly journals An Experimental Investigation of Water Vapor Condensation from Biofuel Flue Gas in a Model of Condenser, (1) Base Case: Local Heat Transfer without Water Injection

Processes ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 844
Author(s):  
Robertas Poškas ◽  
Arūnas Sirvydas ◽  
Vladislavas Kulkovas ◽  
Povilas Poškas
Keyword(s):  
Heat Transfer ◽  
Water Vapor ◽  
Flue Gas ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Water Injection ◽  
Vapor Condensation ◽  
Base Case ◽  
Water Vapor Condensation ◽  
Condensing Heat Exchanger

Waste heat recovery from flue gas based on water vapor condensation is an important issue as the waste heat recovery significantly increases the efficiency of the thermal power units. General principles for designing of this type of heat exchangers are known rather well; however, investigations of the local characteristics necessary for the optimization of those heat exchangers are very limited. Investigations of water vapor condensation from biofuel flue gas in the model of a vertical condensing heat exchanger were performed without and with water injection into a calorimetric tube. During the base-case investigations, no water was injected into the calorimetric tube. The results showed that the humidity and the temperature of inlet flue gas have a significant effect on the local and average heat transfer. For some regimes, the initial part of the condensing heat exchanger was not effective in terms of heat transfer because there the flue gas was cooled by convection until its temperature reached the dew point temperature. The results also showed that, at higher Reynolds numbers, there was an increase in the length of the convection prevailing region. After that region, a sudden increase was observed in heat transfer due to water vapor condensation.

Heat Exchangers for Cooling Boiler Flue Gas to Temperatures Below the Water Vapor Dewpoint

2011 ◽  
Author(s):  
Edward Levy ◽  
Harun Bilirgen ◽  
Michael Kessen ◽  
Daniel Hazell ◽  
Barbara Carney
Keyword(s):  
Heat Transfer ◽  
Water Vapor ◽  
Flue Gas ◽  
Heat Exchangers ◽  
Buoyancy Force ◽  
Power Plants ◽  
Vapor Condensation ◽  
Water Vapor Condensation ◽  
Funded Project ◽  
Condensed Water

Coal-fired power plants have traditionally operated with stack temperatures in the 300°F range to minimize fouling and corrosion problems due to sulfuric acid condensation and to provide a buoyancy force to assist in the transport of flue gas up the stack. However, as an alternative, there would be benefits to cooling the flue gas to temperatures below the water vapor and acid dew points, while capturing the condensed water vapor. This paper describes experimental results from a DOE and industry-funded project to develop condensing heat exchangers for application to coal-fired power plants. A system of condensing heat exchangers was designed, fabricated and tested using slip streams of boiler flue gas and experiments were performed to measure the effects of process parameters on rates of heat transfer and water vapor condensation. In addition, measurements were made to characterize the acid concentrations in the condensed water which collected on the heat exchanger tubes and to quantify the effects of the heat exchangers on flue gas mercury concentrations.

Methods of Thermal Calculations for a Condensing Waste-Heat Exchanger

2014 ◽  
Vol 35 (4) ◽  
pp. 447-461 ◽  
Author(s):  
Paweł Rączka ◽  
Kazimierz Wójs
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Water Vapour ◽  
Flue Gas ◽  
Waste Heat ◽  
Pilot Scale ◽  
Dew Point ◽  
Steam Boiler ◽  
Heat Transfer Area ◽  
Condensing Heat Exchanger

Abstract The paper presents the algorithms for a flue gas/water waste-heat exchanger with and without condensation of water vapour contained in flue gas with experimental validation of theoretical results. The algorithms were used for calculations of the area of a heat exchanger using waste heat from a pulverised brown coal fired steam boiler operating in a power unit with a capacity of 900 MWe. In calculation of the condensing part, the calculation results obtained with two algorithms were compared (Colburn-Hobler and VDI algorithms). The VDI algorithm allowed to take into account the condensation of water vapour for flue gas temperatures above the temperature of the water dew point. Thanks to this, it was possible to calculate more accurately the required heat transfer area, which resulted in its reduction by 19 %. In addition, the influence of the mass transfer on the heat transfer area was taken into account, which contributed to a further reduction in the calculated size of the heat exchanger - in total by 28% as compared with the Colburn-Hobler algorithm. The presented VDI algorithm was used to design a 312 kW pilot-scale condensing heat exchanger installed in PGE Belchatow power plant. Obtained experimental results are in a good agreement with calculated values.

scholarly journals An Experimental Investigation of Water Vapor Condensation from Biofuel Flue Gas in a Model of Condenser, (2) Local Heat Transfer in a Calorimetric Tube with Water Injection

Processes ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1310
Author(s):  
Robertas Poškas ◽  
Arūnas Sirvydas ◽  
Vladislavas Kulkovas ◽  
Hussam Jouhara ◽  
Povilas Poškas ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Flue Gas ◽  
Gas Flow ◽  
Water Injection ◽  
Middle Part ◽  
Total Heat ◽  
Gas Temperature ◽  
Total Heat Transfer ◽  
Condensing Heat Exchanger

In order for the operation of the condensing heat exchanger to be efficient, the flue gas temperature at the inlet to the heat exchanger should be reduced so that condensation can start from the very beginning of the exchanger. A possible way to reduce the flue gas temperature is the injection of water into the flue gas flow. Injected water additionally moistens the flue gas and increases its level of humidity. Therefore, more favorable conditions are created for condensation and heat transfer. The results presented in the second paper of the series on condensation heat transfer indicate that water injection into the flue gas flow drastically changes the distribution of temperatures along the heat exchanger and enhances local total heat transfer. The injected water causes an increase in the local total heat transfer by at least two times in comparison with the case when no water is injected. Different temperatures of injected water mainly have a major impact on the local total heat transfer until almost the middle of the model of the condensing heat exchanger. From the middle part until the end, the heat transfer is almost the same at different injected water temperatures.

Effect of substrate wettability and flexibility on the initial stage of water vapor condensation

Soft Matter ◽  
2019 ◽  
Vol 15 (48) ◽  
pp. 10055-10064
Author(s):  
Qi Che ◽  
Yongjun Lu ◽  
Fenghui Wang ◽  
Xiang Zhao
Keyword(s):  
Heat Transfer ◽  
Water Vapor ◽  
Vapor Condensation ◽  
Transfer Efficiency ◽  
Heat Transfer Efficiency ◽  
Initial Stage ◽  
Water Vapor Condensation ◽  
Condensation Mode

The condensation mode and heat transfer efficiency are significantly affected by substrate wettability and flexibility in the initial stage of vapor condensation.

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